1. Field of the Invention
This invention relates to a method and apparatus for diagnosing a disease of a subject by analyzing substances contained in body fluids such as urine and blood by means of chromatography and evaluating the results of analysis on the chromatograms thus obtained.
2. Description of the Prior Art
Various disease diagnostic apparatus such as physical measuring apparatus, for example, a roentogenograph and a cardiograph and biochemical analyzers for body fluid components have been used hitherto in addition to medical consultation and examination by a doctor, and a disease of a subject has been diagnosed on the basis of the results of measurement by such diagnostic apparatus. Since the result of measurement by a single diagnostic apparatus does not provide the data required for decisive diagnosis of a disease in many cases, the results of measurement by a plurality of different diagnostic apparatus are combined for the determination of a disease, resulting in complexity of the process of disease diagnosis.
It is known that more than a thousand kinds of substances are contained in a body fluid such as urine or blood, and a disease of a subject can be accurately determined by analyzing as many substances as possible. Chromatographic methods such as liquid chromatography and gas chromatography is suitable for simultaneous analysis of such many kinds of substances in a body fluid. However, it is difficult, as a matter of fact, to utilize so many substances for the determination of a disease when a chromatogram is to be evaluated manually.
A method of diagnosing a disease of a subject by analyzing the amounts of amines and amino acids in urine by means of liquid chromatography, analyzing the amounts of volatile compounds in urine by means of gas chromatography, processing the chromatograms thus obtained and determining a disease by the pattern recognition technique, is reported by A. B. Robinson and L. Pauling in a paper entitled "Techniques of Orthomolecular Diagnosis" in "CLINICAL CHEMISTRY", Vol. 20, No. 8, 1974, pp. 961-965.
In this reported method for disease diagnosis, chromatogram patterns are obtained for each of a group of people with various human diseases and another group of people who apparently are normal but who represent differences in age, sex, diet, physical activity and other factors. When the patterns are found, a calculation is carried out in which each subject is classified according to its correlation with the different patterns. The test for a pattern is carried out by calculating the probability, P, that each substance is systematically different in its value for the two different groups. The disease is determined on the basis of the relation of the number of substances with the maximum value of the probability P.